Document JJ1198Mz6Zy6jOww0d4KajVvr

FILE NAME: Talc (TALC) DATE: 1973 Feb 14 DOC#: TALC446 DOCUMENT DESCRIPTION: Memo RE Talc Producers' Association Proposed * - " Greenwood Plaza - 3 West February 14, 1973 ' > *4 - P.'a , Martinson - 2 West CALC PRODUCER'S ASSOCIATION tPROPOSED) H. s . L a m a r 's letter of January. 31, 1973 Dick Lamar's letter suggested .that I comment on the technical . soundness of the letter before it is sent. Before doing so, I would like to raise a question as to the desirability of sending such a letter ou' after, attending the recent meeting of-the Talc Producer's Association in New York City. Whilo^ the intent of the meeting was to promulgate a scries of defi nitions differentiating asbestos, tremolite, talc and commer cial talc, I believe I was instrumental in changing the end result so that only one definition is being proposed, i.e., industrial talc. ' While the exact wording may differ very slightly from the definition below, the general gist was as. follows: "Industrial talc is a product varying in mineral composition from the mineral talc . (SigO^o) vOH>43 to mixtures of mineral talc and other naturally associated non-fibrous and/or fibrous minerals as defined by ASTM Designation D2946-71. While we should clear with the Vanderbilt people whether they intend to continue their previous plan to convince Government officials that tremolite is not an asbestos mineral, my own impression from the meeting is that.they are convinced of ^he futility of this approach. Th(e much more reasonable approach, and one which has some slight possibility of bearing fruit, is to concentrate on the definition of fiber. The AGTM definition referred to.above uses an aspect.ratio of 1 0 : 3 rather than the ACGIH ratio of 3:1. r , T, Vanderbilt appears to be the spearhead for the whole effort to disassociate tremolite from the list of asbestos minerals. If they are not going to push this approach, then there is little need, in my opinion, for sending the letter to' Talc Producers or to the Talc Producer s Association. So much for the political aspects of the letter. With reference to the technical aspects, I should like to make the following points, some of which obviously will be minor. CRMC-HT-TALC-000058 February 14, 1973 . Pago 2 p. A. Martinson - 2 West rtni 2. While tremolite does have a fibrous "crystal habit" f i b e r a the "'particles can be fibrous or non -fibrous. In is a particle with defined minimum ratio essence, a of length . to width. Unfortunately, this aspect ratio ;{L/D) is not a definitely established limit. As a matter of fact, in the ASTM definition's there re two ratios given as minimum. In the ASTM definition of asbestos minerals, the ratio is 10:lp .in the Textile Fiber section, the limit is given as 100:1. Howe 'or, the more important aspect ratio limit, whether it has any more scientific significance or not, is that promulgated by the ACGIIi, namely,' an aspect ratio of 3. If the tremolite particles have an aspect ratio greater than 3:1, they are fibrous as far as OSHA is concerned. If the ratio is loss than 3:1, the tremolite particle is a particle, not a fiber. Thus, although "tremolite is a fibrous mineral" as stated in Item 2, the individual particles may be fibrous or may not be fibrous, depending on their specific aspect ratios. Starting with this distinction, we go to Item 1 which says that tremolite is clearly a member of the "asbestos family" of minerals. Again, this is correct, but since the asbestos minerals are fibrous by definition', then we could conclude that those particles of tremolite whose aspect ratio is ex tremely small are really not fibers and, therefore, they could be considered as not being asbestos. What I am trying to point out is that whether tremolite is to be classed as an asbestos minera is secondary to whether the particles are really fibrous or not insofar as the OSHA regulations are concerned, and we should try to pin our argu ments on the aspect ratio factor. . Item 3. X-ray diffraction methods make possible a positive^ "differentiation between" both minerals. It will not definite!}, identify tremolite in a mixture containing small quantities of .tremolite in a large concentration of talc. Strongest identifying X-ray linos for tremolite are essentially the same as those for anthophyllite and several other amphibolc minerals. The statement that pure talc mineral is fairly common in natuxe is something that I must defer to P. Lamar's knowledge. I had not anticipated that there were any large deposits of pure talc mineral without concomitant impurities, albeit non-fibrous impurities such as carbonates, oxides, etc. CEMC-HT-TALC-000059 ,, * .' ' - , February 14 , 1973 Pag 3 . ' p. A. Martinson - 2 West , { Item 8 While I am sux*e that our Industrial Hygienists can supply" information-regarding correct procedures for dust control and other protective measures that may be required, it will be a long time before sufficient medical or epidemio logical data are available on which to pass any recommendations other than to include trcmo^-ite as either an asbestos fiber, in which case the fiber count limitations will be paramount, or as a nuisance dust in which particle count would be para mount-. . Dick Lamar is to be congratulated on preparing a summation of this type which brings together at one point pertinent informa tion of a technical nature. . S. SPEIL SS/rs ecu W. L. J, M. ir. r . w. c. R. P. R. S. E. B. R. F. VanDorbeek Sharratt Keefe Streib Carter Lamar Smith Bassett - 2 West - 2 West - .2 West - 3 West - 5 West - 1 North - Long Beach, - Long Beach, Carson Carson CRMC-HT-TjVLC-000060